Fungus

A fungus is an organism that can grow on living and nonliving
things. Fungi (the plural of fungus) include many types of organisms including
yeasts, mold, and mushrooms. Fungi that cause problems for people include
yeasts and molds and other types of fungi.

In some situations,
fungi can infect and damage tissue, such as skin, hair, or nails. Fungi also
may be involved in infections throughout the body, such as in the central
nervous system or the bloodstream.